We were passing through the Texas panhandle last week and stopped in for a visit at the Jack Sizemore RV Museum in Amarillo. It was a nice stop and it felt like stepping back in time. There were numerous vintage RV's, including the first Airstream, the Flxible Bus RV from the movie "RV", a number of well-known brands, and some I'd never heard of prior to the visit. You can step up into most of them and get a closer look, too.
While they don't have a Hi-Lo in the museum, they did have a 1973 Tow-Low with the manual lift mechanism, and the "wheel" that turns it, located at the front of the trailer.
The RV museum is free and convenient to the interstate. There are also a number of vintage motorcycles, including a 1918 Harley Davidson that is one of only two known to exist, and a 1942 US military motorcycle fully restored.
Jack Sisemore Traveland RV Museum